Table 2 Dynamic image analysis shape parameters of interest
Parameter | Definition |
|---|---|
Sphericity (SPHT) | The sphericity (SPHT) is a measure of the roundness of a grain. It depends on particle area (A) and perimeter (P): \(\mathrm{SPHT}=\frac{4\mathrm\pi\mathrm A}{\mathrm P^2}\) For a perfect circle SPHT = 1, for all other shapes SPHT < 1 |
Elongation (aspect ratio) (b/l) | The aspect ratio (b/l) is a measure of the elongation of a grain. It is determined by the particle width/length ratio of the grain (the closer to 1, the more circular the grain): \(\frac{\mathrm b}{\mathrm l}=\frac{{\mathrm x}_{\mathrm{cmin}}}{{\mathrm x}_{\mathrm{Femax}}}\mathrm{or}\frac{\mathrm{particle}\;\mathrm{width}}{\mathrm{particle}\;\mathrm{length}}\) |
Compactness (Compact) | The compactness (Compact) is a measure of the roundness of a grain. It depends on particle area (A) and particle length (\({x}_{Fe \text{max}}\)): \(\mathrm{Compact}=\frac{\sqrt{\frac{4\mathrm A}{\mathrm\pi}}}{\mathrm l}\) For a perfect circle Compact = 1, for all other shapes Compact < 1 |
Krumbein roundness (RDNS) | The Krumbein roundness (RDNS) is a measure of the textural roughness of a grain. The parameter RDNS assigns a value between 0 and 1 to mimic the Krumbein roundness classification scheme (Krumbein 1941). Lower values mean higher roughness |